On Wednesday, The Trump administration is set to announce a “massive” tax plan it hopes to get passed by the end of the year, if not sooner. Given the historic embarrassment that was the G.O.P.’s failure to repeal or replace Obamacare in March, and considering Team Trump’s desperate need for a legislative win ahead of the president’s 100th day in office, you might expect the White House to unveil a plan that has a chance of actually being approved by Congress—or at least one that is sufficiently palatable to Republicans. But you would expect wrong! Instead, Trump has reportedly ordered White House aides to draft a plan that slashes the corporate tax rate to 15 percent, deficits be damned.

That’s not likely to go over well on Capitol Hill, which occasionally still pretends to care about the national debt. House Republicans had previously called for a 25 percent rate, and leadership is currently seeking a 20 percent rate plus a border adjustment tax—a controversial revenue driver that would raise more than a trillion dollars over 10 years but that Trump has reportedly dismissed as too complicated. Without enough business tax breaks available to offset the gargantuan hole Trump’s plan would blow in the budget, it’s hard to see how Paul Ryan signs off on this monstrosity. At the very least, the president and the House Speaker are due for a series of very uncomfortable meetings. Per Bloomberg:

The Ryan-backed House G.O.P. blueprint released in June calls for replacing the 35 percent rate with a 20 percent rate applied to companies’ domestic sales and imported goods, while exempting their exports. Ryan has questioned whether a 15 percent rate can realistically be paid for, and he and Kevin Brady, chairman of the tax-writing House Ways and Means Committee, have said they’re committed to revenue neutrality.

The Urban-Brookings Tax Policy Center estimates that cutting the corporate rate to 20 percent would lower federal tax revenue by $1.8 trillion over a decade, while cutting it to 15 percent would decrease revenue by $2.4 trillion.

As Bloomberg notes, the White House has already given up on the wildly unpopular border-adjustment tax, and seemingly has no other ideas for ways to raise revenue other than to repeat the old Republican maxim that the tax cuts will pay for themselves. Though as the Tax Policy Center’s Robert Williams told Bloomberg, “History belies that. We haven’t seen tax cuts actually pay for themselves.”

Even if Trump can bring enough Republicans on board, Senate Majority Leader Mitch McConnell would almost certainly have to pass the legislation through the budget reconciliation process to avoid a Democratic filibuster. But Senate rules currently prohibit the passage of any bills that increase the deficit outside the 10-year time frame—which means that Trump’s “phenomenal” tax plan would have an expiration date. In the immortal words of the commander-in-chief: “Sad!”